Circulatory Valve, System and Method

ABSTRACT

Apparatuses, systems, and methods for use in a vascular system. The apparatus include a circulatory valve having a valve frame in which frame members define frame cells. Frame cells include joints in opposing relationship, where the joints transition from a first stable equilibrium state through an unstable equilibrium state to a second stable equilibrium state as the joints are drawn towards each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority to applicationof Ser. No. 11/881,220, filed Jul. 26, 2007, the contents of which arehereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to apparatuses, systems, andmethods for use in the vascular system; and more particularly toapparatuses, systems, and methods for native valve replacement and/oraugmentation.

BACKGROUND

Valves of the vascular system can become damaged and/or diseased for avariety of reasons. For example, damaged and/or diseased cardiac valvesare grouped according to which valve or valves are involved, and theamount of blood flow that is disrupted by the damaged and/or diseasedvalve. The most common cardiac valve diseases occur in the mitral andaortic valves. Diseases of the tricuspid and pulmonary valves are fairlyrare.

The aortic valve regulates the blood flow from the heart's leftventricle into the aorta. The aorta is the main artery that suppliesoxygenated blood to the body. As a result, diseases of the aortic valvecan have a significant impact on an individual's health. Examples ofsuch diseases include aortic regurgitation and aortic stenosis.

Aortic regurgitation is also called aortic insufficiency or aorticincompetence. It is a condition in which blood flows backward from awidened or weakened aortic valve into the left ventricle of the heart.In its most serious form, aortic regurgitation is caused by an infectionthat leaves holes in the valve leaflets. Symptoms of aorticregurgitation may not appear for years. When symptoms do appear, it isbecause the left ventricle must work harder relative to an uncompromisedaortic valve to make up for the backflow of blood. The ventricleeventually gets larger and fluid backs up.

Aortic stenosis is a narrowing or blockage of the aortic valve. Aorticstenosis occurs when the valve leaflets of the aorta become coated withdeposits. The deposits change the shape of the leaflets and reduce bloodflow through the valve. Again, the left ventricle has to work harderrelative to an uncompromised aortic valve to make up for the reducedblood flow. Over time, the extra work can weaken the heart muscle.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the drawing are not to scale.

FIG. 1 illustrates an example of a cardiac valve according to thepresent disclosure.

FIG. 2 illustrates an example of a frame cell according to the presentdisclosure.

FIG. 3 illustrates an example of a joint and compliant section of aframe cell according to the present disclosure.

FIG. 4A illustrates an example of a cardiac valve in an undeployed stateaccording to the present disclosure.

FIG. 4B illustrates an example of the cardiac valve of FIG. 4A in adeployed state according to the present disclosure.

FIG. 5 illustrates an example of a cardiac valve according to thepresent disclosure.

FIG. 6 illustrates an example of a frame cell and a locking mechanismaccording to the present disclosure.

FIG. 7 illustrates an example of a frame cell and a deployment mechanismaccording to the present disclosure.

FIGS. 8A and 8B illustrate a cross-sectional view of an embodiment of asystem that includes a cardiac valve according to the presentdisclosure.

FIG. 8C illustrates a balloon catheter used with an embodiment of thesystem that includes a cardiac valve according to the presentdisclosure.

DETAILED DESCRIPTION

Embodiments of the present invention are directed to apparatuses,systems, and methods for native valve replacement and/or augmentation.For example, the apparatus can include a circulatory valve that can beused to replace an incompetent native valve (e.g., an aortic valve, amitral valve, a tricuspid valve, a pulmonary valve, and/or a venousvalve) in a body lumen. Embodiments of the valve include a valve framehaving frame members defining frame cells with joints that transitionfrom a first stable equilibrium state through an unstable equilibriumstate to a second stable equilibrium state as the joints are drawntowards each other. In one example, embodiments of the presentdisclosure may help to augment or replace the function of a native valveof individuals having heart and/or venous valve disease.

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits. For example, 110 may referenceelement “10” in FIG. 1, and a similar element may be referenced as 210in FIG. 2. As will be appreciated, elements shown in the variousembodiments herein can be added, exchanged, and/or eliminated so as toprovide any number of additional embodiments of a valve and/or a system.In addition, as will be appreciated the proportion and the relativescale of the elements provided in the figures are intended to illustratethe embodiments of the present invention, and should not be taken in alimiting sense.

Various embodiments of the present disclosure are illustrated in thefigures.

Generally, the circulatory valve can be implanted within the fluidpassageway of a body lumen, such as for replacement or augmentation of anative cardiac valve structure within the body lumen (e.g., an aorticvalve), to regulate the flow of a bodily fluid through the body lumen ina single direction.

The embodiments of the circulatory valve of the present disclosureinclude a valve frame that self-expands to a first stable equilibriumstate. The first stable equilibrium state of the valve frame is apartially deployed state relative the deployed state of the circulatoryvalve. In this partially deployed state, the position of the circulatoryvalve relative the desired implant location can be adjusted to correctany foreshortening and/or stent jump that can occur in self-expandingstents as they expand from the small compressed undeployed state. Inaddition, having the circulatory valve in the partially deployed stateprior to completing the deployment allows for adjustments due tomovement caused by the flow output from the ventricle pushing on thedeployment system, which can be the case when implanting an aorticvalve.

As used herein, a partially deployed state of the valve frame liesbetween an undeployed state (i.e., the state of the valve frame at thetime the valve is outside the body) and a deployed state (i.e., thestate of the valve frame at the time the valve is to be left in thebody). Structures on the circulatory valve can then be transitioned fromthe first stable equilibrium state through an unstable equilibrium stateto a second stable equilibrium state to deploy the circulatory valve.

In the various embodiments, holding the valve frame in the partiallydeployed state allows the circulatory valve to be better positioned in adesired location prior to its final deployment. This staged deploymentof the circulatory valve of the present disclosure is in contrast tocirculatory valves that are deployed without the advantage oftemporarily pausing at an intermediate deployment stage (i.e., thepartial deployment state) to allow for adjustments in the placement ofcirculatory valve prior to full deployment.

FIG. 1 provides an embodiment of a circulatory valve 100 of the presentdisclosure. The circulatory valve 100 includes a valve frame 102 and avalve leaflet 104 coupled to the valve frame 102. The valve frame 102also includes frame members 106 that define a frame cell 108. The framecell 108 can include joints 110 that transition from a first stableequilibrium state through an unstable equilibrium state to a secondstable equilibrium state. In one embodiment, this transition can occuras one or more of the joints 110 are drawn towards each other, as willbe discussed herein.

The valve frame 102 has an elongate tubular structure with a proximalend 112 and a distal end 114. In one embodiment, the frame cell 108 ofthe present disclosure can be positioned so as to provide both theproximal and distal ends 112, 114 of the valve frame 102. In otherwords, portions of the frame cell 108 define the proximal and distalends 112, 114 of the valve frame 102. In an additional embodiment, theframe cell 108 of the present disclosure can be located between proximaland distal ends 112, 114 of the valve frame 102 (i.e., portions of theframe cell 108 does not define the proximal end 112 and/or the distalend 114 of the frame 102). In an alternative embodiment, the frame cell108 of the present disclosure can be located at one of either theproximal end 112 or the distal end 114 of the valve frame 102. Differentcombinations are also possible.

For the various embodiments, the joints 110 can be located at a numberof different positions on the frame member 106. For example, the joints110 can be located at the same relative position along the frame member106. So, when a frame cell 108 includes two joints 110, they can be setopposite each other in a mirror image relationship. This aspect of thedisclosure is illustrated in FIG. 1, which shows the circulatory valve100 in the first stable equilibrium state. Alternatively, the joints 110can be at different relative locations along the frame member 106, aswill be discussed herein.

In an additional embodiment, the joints 110 can be located on the framemember 106 such that as the joint 110 transitions from the first stableequilibrium state to the second stable equilibrium state the size (e.g.,length) of the perimeter of the valve frame 102 increases. In otherwords, the joints 110 are located on the frame member 106 in such a wayas to cause the valve frame 102 to radially increase in size as thejoints 110 move toward the second stable equilibrium state. In oneembodiment, the valve frame 102 increases its perimeter size as theframe cell 108 change shape during the joint 110 transition. As will beappreciated, some change to the longitudinal dimension of the valveframe 102 may occur as the perimeter dimension changes.

As discussed, FIG. 1 provides an illustration where the joints 110 ofthe valve frame 102 are in the first stable equilibrium state. In thevarious embodiments, this first stable equilibrium state places thevalve frame 102 in a partially deployed state. As used herein, apartially deployed state of the valve frame lies between an undeployedstate (i.e., the state of the valve frame at the time the valve isoutside the body) and a deployed state (i.e., the state of the valveframe at the time the valve is to be left in the body). The valve frame102 remains in partially deployed state until the joints 110 are movedto the second stable equilibrium state, as discussed herein. In oneembodiment, the valve frame 102 in the first stable equilibrium state iseighty (80) to ninety-five (95) percent of the deployed state. Otherpercentages of the deployed state are possible (e.g., ninety (90)percent of the deployed state).

In the various embodiments, the frame cell 108 can include one or moreof the joints 110. As illustrated in FIG. 1, the frame cells 108 includetwo of the joints 110. In an additional embodiment, each frame cell 108of the valve frame 102 need not have a joint 110. In other words, aframe cell 108 without a joint 110. So, in one embodiment a valve frame102 could be configured in such a way that not every frame cell 108includes a joint 110.

Frame cells 108 not having a joint 110 could be integrated into thevalve frame 102 to provide structural characteristics to the frame 102that are advantageous to the operation of the valve 100. For example,the frame cell 108 without the joint 110 may be more flexible in theradial direction to better accommodate physiological changes at theimplant site. Examples of such design properties include, but are notlimited to, providing an elastic radial force where the frame members106 can have serpentine bends that provide for, at least in part, theelastic radial force. Other shapes and configurations for the frame cell108 (with or without the joint 110) are also possible.

For the various embodiments, the valve frame 102 can be self-expanding.Examples of self-expanding frames include those formed fromtemperature-sensitive memory alloy which changes shape at a designatedtemperature or temperature range. Alternatively, the self-expandingframes can include those having a spring-bias. Examples of suitablematerials include, but are not limited to, medical grade stainless steel(e.g., 316L), titanium, tantalum, platinum alloys, niobium alloys,cobalt alloys, alginate, or combinations thereof. Examples ofshape-memory materials include shape memory plastics, polymers, andthermoplastic materials which are inert in the body. Shaped memoryalloys having superelastic properties generally made from ratios ofnickel and titanium, commonly known as Nitinol, are also possiblematerials. Other materials are also possible.

For the various embodiments, the frame member 106 can have similarand/or different cross-sectional geometries along its length. Thesimilarity and/or the differences in the cross-sectional geometries canbe based on one or more desired functions to be elicited from eachportion of the valve frame 102 and/or the frame cell 108. Examples ofcross-sectional geometries include rectangular, non-planarconfiguration, round (e.g., circular, oval, and/or elliptical),polygonal, arced, and tubular. Other cross-sectional geometries arepossible.

The circulatory valve 100 can further include one or more radiopaque.markers (e.g., tabs, sleeves, welds). For example, one or more portionsof the valve frame 102 can be formed from a radiopaque material.Radiopaque markers can be attached to and/or coated onto one or morelocations along the valve frame 102. Examples of radiopaque materialinclude, but are not limited to, gold, tantalum, and platinum. Theposition of the one or more radiopaque markers can be selected so as toprovide information on the position, location and orientation of thevalve 100 during its implantation.

The circulatory valve 100 further includes the leaflets 104 havingsurfaces defining a reversibly sealable opening for unidirectional flowof a liquid through the valve 100. For example, the leaflets 104 can becoupled to the valve frame 102 so as to span and control fluid flowthrough the lumen of the valve 100. For the present embodiment, thevalve 100 includes two of the valve leaflet 104 for a bi-leafletconfiguration. As appreciated, mono-leaflet, tri-leaflet and/ormulti-leaflet configurations are also possible. The each of the valveleaflet 104 are coupled to the valve frame 102, where the leaflets 104can repeatedly move between an open state and a closed state forunidirectional flow of a liquid through a lumen of the circulatory valve100.

In one embodiment, the leaflets 104 can be derived from autologous,allogeneic or xenograft material. As will be appreciated, sources forxenograft material (e.g., cardiac valves) include, but are not limitedto, mammalian sources such as porcine, equine, and sheep. Additionalbiologic materials from which to form the valve leaflets 104 include,but are not limited to, explanted veins, pericardium, facia lata,harvested cardiac valves, bladder, vein wall, various collagen types,elastin, intestinal submucosa, and decellularized basement membranematerials, such as small intestine submucosa (SIS), amniotic tissue, orumbilical vein.

Alternatively, the leaflets 104 could be formed from a syntheticmaterial. Possible synthetic materials include, but are not limited to,expanded polytetrafluoroethylene (ePTFE), polytetrafluoroethylene(PTFE), polystyrene-polyisobutylene-polystyrene (SIBS), polyurethane,segmented poly(carbonate-urethane), polyester, polyethlylene (PE),polyethylene terephthalate (PET), silk, urethane, Rayon, Silicone, orthe like. In an additional embodiment, the synthetic material can alsoinclude metals, such as stainless steel (e.g., 316L) and nitinol. Thesesynthetic materials can be in a woven, a knit, a cast or other knownphysical fluid-impermeable or permeable configurations. In addition,plated metals (e.g., gold, platinum, rhodium) can be embedded in theleaflet 104 material (e.g., a sandwich configuration) to allow forvisualization of the leaflets 104 post placement.

As will be appreciated, the valve 100 can be treated and/or coated withany number of surface or material treatments. Examples of suchtreatments include, but are not limited to, bioactive agents, includingthose that modulate thrombosis, those that encourage cellular in growth,through growth, and endothelialization, those that resist infection, andthose that reduce calcification.

For the various embodiments, the frame cell 108 also includes acompliant segment 116 that extend between a corner portion 118 and thejoint 110 of the frame cell 108. The compliant segment 116 canelastically flex, or deflect, from the corner portion 118 as the joint110 transitions from the first stable state through the unstable stateto the second stable state. The compliant segment 116 in its deflectedstate can then assist in holding the joint 110 in the second stableequilibrium state.

In one embodiment, the combination of the joint 110 and the compliantsegment 116 provide for a bistable compliant mechanism. The bistablecompliant mechanism used in frame cell 108 includes two stableequilibrium states within its range of motion. In the presentembodiments, these are the first stable equilibrium state and the secondstable equilibrium state, with an unstable equilibrium state positionedthere between. The bistable mechanism used in the present disclosuredoes not require power input for the joint 110 of the cell 108 to remainstable at each equilibrium state. The states of stable equilibrium areessentially positions of relative potential energy minimums to which thejoints 110 and the compliant segment 116 of the frame cells 108 returnwhen the unstable equilibrium state is not achieved.

FIG. 2 provides an illustration of joint 210 and compliant segment 216transitioning from the first stable equilibrium state 222 through theunstable equilibrium state 224 to the second stable equilibrium state226. In one embodiment, this transition occurs as the joint 210 aredrawn towards each other. Embodiments illustrating how this force can beapplied to the joint 210 and the compliant segment 216 will be describedherein.

In addition to illustrating the transition of joint 210 and thecompliant segment 216, FIG. 2 also provides a graph 230 that illustratesthe relative position of the equilibrium states 222 and 226 of the joint210 and compliant segment 216 as a function of potential energy 232. Asillustrated in graph 230, the first and second stable equilibrium states222 and 226 of the joint 210 and the compliant segment 216 are locatedat local potential energy minimums (either equal or unequal) with theunstable equilibrium state 224 positioned between the two states 222 and226. The graph 230 also illustrates that due to the elastic nature ofthe joint 210 and compliant segment 216 changes to their shape away fromthe first stable equilibrium state 222 will not result in transition tothe second stable equilibrium state 226 unless enough force is suppliedto overcome the unstable equilibrium state 224.

FIG. 2 also illustrates how the longitudinal length 228 of the framecell 208 is greater in the second stable equilibrium state 226 ascompared to the first stable equilibrium state 222. This change inlongitudinal length 228 of the frame cell 208 helps to increase theperipheral length of the valve in which the frame cell 208 is used, asdiscussed herein.

As will be appreciated, the configuration and design of the joint 210and the compliant segment 216 for the cell 208 can change the relativevalues for the first and second stable equilibrium states 222, 226. Forexample, such design aspects as a radius of curvature and arc length,among others, for the corner portions 218 and/or the compliant segment216 can affect relative values for the first and second stableequilibrium states 222, 226. In addition, the number, the position andthe configuration of the joint 210 on each frame cell 208 can alsoaffect relative values for the first and second stable equilibriumstates 222, 226. Changes to the cross-sectional shape and/or relativedimensions of the member 206 of the different components (e.g., thejoint 210 and the compliant segment 216) can also affect relative valuesfor the first and second stable equilibrium states 222, 226.

For the various embodiments, the joint of the present disclosure canhave a number of different configurations. For example, the joint 210illustrated in FIG. 2 has a looped configuration, where the frame member206 curves over on itself to form a closed curve. In one embodiment, theframe member 206 can be curved over on itself more than once.

In an alternative embodiment, the frame member forming the joint canhave a partially open configuration. FIG. 3 provides an illustration ofsuch a partially open configuration for the joint 310. As illustrated,the frame member 306 includes a curve 334 that extends for less than acomplete loop.

FIGS. 4A and 4B provide an additional embodiment of the valve 400according to the present disclosure. The valve 400 includes the valveframe 402 and valve leaflet 404 coupled to the valve frame 402. Thevalve frame 402 also includes frame members 406 that define a frame cell408 having joints 410, as discussed herein. FIG. 4A provides anillustration of the valve 400 in an undeployed state, where as FIG. 4Bprovides an illustration of the valve 400 in a deployed state (e.g.,where the joints 410 are in their second stable equilibrium state 426).As illustrated, the joints 410 have a partially open configuration witha curve 434.

The joints 410 illustrated in FIGS. 4A and 4B also include an opening435 defined by the valve frame 402. In one embodiment, the openings 435defined by the valve frame 402 can be used to advance the joints 410 ofthe valve frame 402 from the first stable equilibrium state through theunstable equilibrium state to the second stable equilibrium state. Inone embodiment, this transition can occur as one or more of the joints410 are drawn towards each other, as will be discussed herein.

The valve frame 402 has an elongate tubular structure with a proximalend 412 and a distal end 414. In one embodiment, the frame cell 408 ofthe present disclosure can be positioned so as to provide both theproximal and distal ends 412, 414 of the valve frame 402. Otherconfigurations are possible, as discussed herein.

As illustrated, the joints 410 are located on the frame member 406 suchthat as the joints 410 transition to the second stable equilibrium statethe size (e.g., length) of the perimeter of the valve frame 402increases. In other words, the joints 410 are located on the framemember 406 in such a way as to cause the valve frame 402 to radiallyincrease in size as the joints 410 move toward the second stableequilibrium state. In one embodiment, the valve frame 402 increases itsperimeter size as the frame cell 408 change shape during the joint 410transition. As will be appreciated, some change to the longitudinaldimension of the valve frame 402 may occur as the perimeter dimensionchanges.

For the various embodiments, the valve frame 402 can be self-expanding,as discussed herein. For the various embodiments, the frame member 406can also have similar and/or different cross-sectional geometries alongits length, as discussed herein. The circulatory valve 400 can furtherinclude one or more radiopaque markers (e.g., tabs, sleeves, welds), asdiscussed herein.

FIG. 5 provides an additional embodiment of the valve 500 according tothe present disclosure. The valve 500 includes the valve frame 502 andvalve leaflet 504 coupled to the valve frame 502. The valve frame 502also includes frame members 506 that define a frame cell 508 havingjoints 510, as discussed herein. As illustrated, while the frame cells508 are located at the proximal end 512 and distal end 514 of the valveframe 502 not every frame cell 508 includes a joint 510. In addition,joints 510 in the frame cells 508 have different relative locationsalong the frame member 506.

FIG. 5 also illustrates that the valve frame 502 has frame members 506that define a predefined frame design 540 that extends between the framecells 508. As illustrated, the predefined frame design 540 and the framecells 508 have a different configuration. Selection of the predefinedframe design 540 can be based on a number of factors. Such factorsinclude, but are not limited to, the location where the valve 500 is tobe implanted, the size of the valve 500, the material(s) used to formthe valve frame 502 of the valve 500, among others. Examples of otheruseful frame designs include those illustrated in co-pending U.S. patentapplication Ser. No. 60/899,444 entitled “Percutaneous Valve, System andMethod” (atty docket number 07-00015P).

FIG. 6 provides an additional embodiment of the present disclosure inwhich the frame cell 608 includes a lock mechanism 644. In the variousembodiments, the lock mechanism 644 can engage to prevent the frame cell608 from transitioning from the second stable equilibrium state. Asillustrated, the lock mechanism 644 of the present embodiment caninclude a first engagement member 646 and a second engagement member 648that can engage so as to lock together.

In one embodiment, the first and second engagement members 646, 648 onthe frame cell 608 engage to lock together as the frame cell 608 movesfrom the unstable equilibrium state 624 to the second stable equilibriumstate 626. As illustrated, the first engagement member 646 extends fromone of the joints 610 (e.g., a first joint), while the second engagementmember 648 extends from another of the joint 610 (e.g., a second joint)of the frame cell 608. Alternatively, the engagement members can extendfrom portions of the compliant segments 616 of the frame cell 608. Forthe various embodiments, the locking mechanism 644 can allow the secondstate 626 to be something other than a local potential energy minimum,as it better ensures the frame cell 608 does not return to its firststable equilibrium state 622.

The lock mechanism 644 used with the frame cell 608 can take a number ofdifferent forms and configurations. For example, first engagement member646 of the lock mechanism 644 can include a shaft having a ball tip. Thesecond engagement member 648 can have a socket to receive and lock theball tip of the shaft. Alternatively, the first engagement member 646 ofthe lock mechanism 644 can include a shaft having a hook. The secondengagement member 648 can have a loop or member segment to receive andengage the hook to lock the frame cell 608. In one embodiment, the loopof the second engagement member 648 could be either the loop of thejoint 610 or a portion of the frame member 606, which are opposite toand functionally aligned with the hook.

FIG. 7 provides an illustration of a deployment mechanism 750 used totransition the joint 710 the first stable equilibrium state 722 throughthe unstable equilibrium state 724 to the second stable equilibriumstate 726. As illustrated, the deployment mechanism 750 can be used toapply a force to draw the joints 710 towards each other. Upon reachingthe second stable equilibrium state 726, the deployment mechanism 750can be removed from the joints 710 of the frame cell 708.

For the present embodiment, the deployment mechanism 750 includes a pushtube 752 having a lumen 754, and a deployment thread 756 that extendsthrough the lumen 754. The push tube 752 includes a distal end 758 thatcan abut a first of the joints 710. The deployment thread 756 extendsfrom the lumen 754 and loops through a second of the joints 710positioned across from the first of the joints 710. A pulling force 760can be applied through the deployment thread 756 and/or a pushing force762 can be applied through the push tube 752 to apply force to draw thejoints 710 towards each other.

Upon reaching the second stable equilibrium state 726, the deploymentthread 756 can be removed from the joint 710 by pulling on a first endof thread 756 to allow the second end of the thread 756 to pass throughthe joint 710. The thread 756 and the push tube 752 can then be removedfrom the frame cell 708. Other ways of removing the thread 756 from theframe joint 710 are also possible.

For the various embodiments, the deployment thread 756 can have a numberof different configurations. For example, the deployment thread 756 canbe a monofilament (i.e., a single strand of material). Alternatively,the deployment thread 756 can have a multistrand configuration. Forexample, the deployment thread 756 having multiple strands can have awoven, a braided, and/or a twisted configuration. Combinations of theseconfigurations are also possible.

The deployment thread 756 can also have a multilayer construction, wherethe deployment thread 756 includes a core that is surrounded by one ormore layers. The core and layers of the deployment thread 756 can beformed of different materials and/or the same materials having differentdesired properties. In addition, the deployment thread 756 can furtherinclude a coating that does not necessarily constitute a “layer” (i.e.,a material that imbeds or integrates into the layer on which it isapplied). Such layers and/or coatings can impart properties to thedeployment thread 756 such as hardness and/or lubricity, among others.

The deployment thread 756 can be formed of a number of materials. Suchmaterials can have a sufficient tensile strength and yield point toresist stretching so as to allow the frame cells of the presentdisclosure to be deployed as discussed herein. Examples of suchmaterials include, but are not limited to, polymers such as nylon(s),acetal, Pebax, PEEK, PTFE, polyamide, polypyrol, and Kevlar.Alternatively, the deployment thread 756 can be formed of metal and/ormetal alloys, such as stainless steel, elgioly, nitinol, and titanium.Other polymers, metals and/or metal alloys are also possible. The thread756 could also be coated with a lubricious material, such as ahydrophilic coating. The materials of the deployment thread 756 alsoinclude combinations of these materials in one or more of theconfigurations as discussed herein.

The push tube 752 can formed from a number of different materials.Materials include metal(s), metal alloys, and polymers, such as PVC, PE,POC, PET, polyamide, mixtures, and block co-polymers thereof. Inaddition, the push tube 752 can have a wall thickness and a lumendiameter sufficient to allow the deployment thread 756 to slidelongitudinally through the lumen 754 and to have sufficient columnstrength to apply the pushing force 762, as discussed herein.

FIGS. 8A and 8B illustrate a cross-sectional view of an embodiment of asystem 866 according to the present disclosure. System 866 includescirculatory valve 800, as described herein, releasably joined to anelongate delivery catheter 868. The system 866 also includes aretractable sheath 870, where the circulatory valve 800 is releasablypositioned between the sheath 870 and the delivery catheter 868. Forexample, FIG. 8A illustrates an embodiment in which the retractablesheath 870 is positioned around at least a portion of the deliverycatheter 868 to releasably hold the valve 800 in an undeployed state.FIG. 8B illustrates an embodiment in which the sheath 870 has beenretracted relative the delivery catheter 868 to allow the valve 800 toexpand to its partially deployed state.

In the example, the delivery catheter 868 includes an elongate body 872having a proximal end 874 and a distal end 876. A lumen 878 extendsthrough the proximal and distal ends 874, 876. In one embodiment, thelumen 878 receives a guidewire for guiding the placement of thecirculatory valve 800 in the vasculature.

For the various embodiments, the elongate delivery catheter 868 alsoincludes a distal tip 880. For the various embodiments, the distal tip880 has a conical configuration, where the tip 880 has a smallerdiameter portion near the distal end 876 of the of the delivery catheter868 as compared to the proximal portion of the tip 880. The distal tip880 can also include a recessed lip 882 in which a distal portion of theretractable sheath 870 can releasably seat. In one embodiment, seatingthe distal portion of the retractable sheath 870 in the recessed lip 882helps to hold the valve 800 in its undeployed state.

The retractable sheath 870 can move longitudinally (e.g., slide)relative the delivery catheter 868 to allow the circulatory valve 800 toexpand from its undeployed state towards the first stable equilibriumstate. In one embodiment, moving the retractable sheath 870 relative thedelivery catheter 868 can be accomplished by pulling, a proximal portion884 of the sheath 870 relative a proximal portion 886 of the deliverycatheter 868.

The system 866 also includes push tubes 852 and deployment thread 856for a deployment mechanism, as discussed herein. As illustrated, thepush tubes 852 are positioned between the sheath 870 and the deliverycatheter 868. The push tubes 852 also include a proximal portion 888from which the tubes 852 can be moved longitudinally relative the sheath870 and the delivery catheter 868. In one embodiment, the proximalportion 888 allows a user to apply a pushing force through the tubes 852to the joints 810, as discussed herein. For the various embodiments, thedeployment thread 856 extends from the lumen 854 of the push tubes 852,where both the deployment thread 856 and at least the distal end 859 ofthe push tubes 852 releasably engage the joints 810 of the frame cell808.

As illustrated in FIG. 8B, the circulatory valve 800 expands to itsfirst stable equilibrium state, as discussed herein, after theretractable sheath 870 has been retracted relative the valve 800. Thepush tubes 852 are illustrated as bending with the valve 800 in itsfirst stable equilibrium state. The push tubes 852 are also illustratedas abutting the first of the joint 810 while the deployment thread 856loops through the second of the joint 810 for the frame cell 808. Forceapplied through the deployment threads 856 and/or the push tubes 852 canthen be used to transition the valve 800 from the first stableequilibrium state to the second stable equilibrium state, as discussedherein.

Embodiments of the system 866 can further include an expandable filterthat forms a portion of the retractable sheath. Examples of such anembodiment can be found in co-pending U.S. patent application Ser. No.12/012,911, entitled “Percutaneous Valve, System and Method” (docketnumber 07-00015US), which is hereby incorporated by reference in itsentirety.

Each of the delivery catheter 868, the retractable sheath 870 can beformed of a number of materials. Materials include polymers, such asPVC, PE, POC, PET, polyamide, mixtures, and block co-polymers thereof.In addition, each of the delivery catheter 868 and the retractablesheath 870 can have a wall thickness and an inner diameter sufficient toallow the structures to slide longitudinally relative each other, asdescribed herein, and to maintain the circulatory valve 800 in acompressed state, as discussed herein.

As discussed herein, applying force between the push tubes 852 and thedeployment thread 856 allows the frame cells 808 to transition to thesecond stable equilibrium state (e.g., the deployed state). Additionalapproaches to transitioning frame cells 808 to the second stableequilibrium state (e.g., the deployed state) are also possible. Forexample, two or more deployment threads could be used for each framecell to draw the joints into the second stable equilibrium state.Alternatively, the frame cells could abut the retractable sheath at aproximal end of the stent, while deployment threads are used to draw thejoints into the second stable equilibrium state. Other configurationsare also possible.

In an additional embodiment, seating of the valve 800 in its deployedstate within the vasculature can be assisted by radially expanding thevalve 800 with a balloon catheter. For example, FIG. 8C provides anillustration of the valve 800 after the push tubes and the deploymentthread have been removed from the valve frame 802. A balloon catheter892 having an inflatable balloon 894 can be positioned in the lumen ofthe valve 800. The balloon 894 can be inflated with fluid supplied by aninflation device 896 through catheter lumen 898 in fluid communicationwith the balloon 892. In one embodiment, the balloon 894 can have a “dogbone” shape, where the bulbous ends of the balloon are aligned with theframe cells 808 of the valve 800. The balloon 892 can then contact andradially expand the valve frame 802 to better ensure that the valve 800is deployed.

In an additional embodiment, the circulatory valve 800 can furtherinclude a sealing material 801 positioned on the periphery of the valveframe 802. In one embodiment, once implanted the tissue the sealingmaterial 801 can swell due the presence of liquid to occupy volumebetween the valve frame 802 and the tissue on which the valve 800 hasbeen implanted so as to prevent leakage of the liquid around the outsideof the circulatory valve 800.

A variety of suitable materials for the sealing material 801 arepossible. For example, the sealing material 801 can be selected from thegeneral class of materials that include polysaccharides, proteins, andbiocompatible gels. Specific examples of these polymeric materials caninclude, but are not limited to, those derived from poly(ethylene oxide)(PEO), polyethylene terephthalate (PET), poly(ethylene glycol) (PEG),poly(vinyl alcohol) (PVA), poly(vinylpyrrolidone) (PVP),poly(ethyloxazoline) (PEOX) polyaminoacids, pseudopolyamino acids, andpolyethyloxazoline, as well as copolymers of these with each other orother water soluble polymers or water insoluble polymers. Examples ofthe polysaccharide include those derived from alginate, hyaluronic acid,chondroitin sulfate, dextran, dextran sulfate, heparin, heparin sulfate,heparan sulfate, chitosan, gellan gum, xanthan gum, guar gum, watersoluble cellulose derivatives, and carrageenan. Examples of proteinsinclude those derived from gelatin, collagen, elastin, zein, andalbumin, whether produced from natural or recombinant sources.

The embodiments of the valve described herein may be used to replace,supplement, or augment valve structures within one or more lumens of thebody. For example, embodiments of the present invention may be used toreplace an incompetent cardiac valve of the heart, such as the aortic,pulmonary and/or mitral valves of the heart. In one embodiment, thenative cardiac valve can either remain in place (e.g., via avalvuloplasty procedure) or be removed prior to implanting thecirculatory valve of the present disclosure.

In addition, positioning the system having the valve as discussed hereinincludes introducing the system into the cardiovascular system of thepatient using minimally invasive percutaneous, transluminal techniques.For example, a guidewire can be positioned within the cardiovascularsystem of a patient that includes the predetermined location. The systemof the present disclosure, including the valve as described herein, canbe positioned over the guidewire and the system advanced so as toposition the valve at or adjacent the predetermined location. In oneembodiment, radiopaque markers on the catheter and/or the valve, asdescribed herein, can be used to help locate and position the valve.

The valve can be deployed from the system at the predetermined locationin any number of ways, as described herein. In one embodiment, valve ofthe present disclosure can be deployed and placed in any number ofcardiovascular locations. For example, valve can be deployed and placedwithin a major artery of a patient. In one embodiment, major arteriesinclude, but are not limited to, the aorta. In addition, valves of thepresent invention can be deployed and placed within other major arteriesof the heart and/or within the heart itself, such as in the pulmonaryartery for replacement and/or augmentation of the pulmonary valve andbetween the left atrium and the left ventricle for replacement and/oraugmentation of the mitral valve. The circulatory valve can also beimplanted in the leg veins (e.g., iliac, femoral, great saphenous,popliteal, and superficial saphenous). Other locations are alsopossible.

As discussed herein, the circulatory valve can be deployed in a stagedfashion. In the first stage, the valve is held in its undeployed state(e.g., compressed state) by the retractable sheath. The retractablesheath can then be moved (e.g., retracting the sheath) to allow thevalve to radially expand from the undeployed state to the first stableequilibrium state. The joints of the valve frame can then betransitioned from the first stable equilibrium state through theunstable equilibrium state to the second stable equilibrium state todeploy the circulatory valve, as discussed herein. In an additionalembodiment, the circulatory valve can also be radially expanded with aninflatable balloon to set the circulatory valve in the deployed state.

Once implanted, the valve can provide sufficient contact with the bodylumen wall to prevent retrograde flow between the valve and the bodylumen wall, and to securely locate the valve and prevent migration ofthe valve. The valve described herein also display sufficientflexibility and resilience so as to accommodate changes in the bodylumen diameter, while maintaining the proper placement of valve. Asdescribed herein, the valve can engage the lumen so as to reduce thevolume of retrograde flow through and around valve. It is, however,understood that some leaking or fluid flow may occur between the valveand the body lumen and/or through valve leaflets.

While the present invention has been shown and described in detailabove, it will be clear to the person skilled in the art that changesand modifications may be made without departing from the spirit andscope of the invention. For example, the pulling mechanism illustratedherein could be used to mechanically expand a valve frame of other typesof self-expanding stents and/or valve frames to enlarge thecross-sectional size (e.g., the diameter) to its fullest dimension. Assuch, that which is set forth in the foregoing description andaccompanying drawings is offered by way of illustration only and not asa limitation. The actual scope of the invention is intended to bedefined by the following claims, along with the full range ofequivalents to which such claims are entitled. In addition, one ofordinary skill in the art will appreciate upon reading and understandingthis disclosure that other variations for the invention described hereincan be included within the scope of the present invention.

In the foregoing Detailed Description, various features are groupedtogether in several embodiments for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the embodiments of the invention requiremore features than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus, the following claimsare hereby incorporated into the Detailed Description, with each claimstanding on its own as a separate embodiment.

What is claimed is:
 1. A method for staged deployment of a circulatoryvalve, comprising: radially expanding a valve frame of the circulatoryvalve from an undeployed state to a first stable equilibrium state; andtransitioning joints of the valve frame from the first stableequilibrium state through an unstable equilibrium state to a secondstable equilibrium state to deploy the circulatory valve.
 2. The methodof claim 1, where radially expanding the valve frame from the undeployedstate includes releasing the circulatory valve from the undeployedstate.
 3. The method of claim 1, where transitioning the joints from thefirst stable equilibrium state through the unstable equilibrium state tothe second stable equilibrium state includes drawing the joints in eachof a frame cell toward each other.
 4. The method of claim 3, wherestopping the movement of the joints in each frame cell before passingthe unstable equilibrium state causes the joints to return toward thefirst stable equilibrium state.
 5. The method of claim 1, wheretransitioning joints of the valve frame include pulling the jointsthrough the unstable equilibrium state to the second stable equilibriumstate.
 6. The method of claim 1, including locking the valve frame inthe second stable equilibrium state with a lock mechanism.
 7. The methodof claim 1, including flexing a compliant segment of the valve frame asthe joints of the valve frame transition from the first stableequilibrium state through the unstable equilibrium state to the secondstable equilibrium state to help hold the circulatory valve in thedeployed state.
 8. The method of claim 1, where transitioning the jointsincludes elastically deforming the joints from the first stableequilibrium state through the unstable equilibrium state to the secondstable equilibrium state to deploy the circulatory valve.
 9. The methodof claim 1, where radially expanding the valve frame includes expandingthe valve frame to eighty (80) to ninety-five (95) percent of the secondstable equilibrium state for the first stable equilibrium state.
 10. Asystem, comprising: an elongate delivery catheter; a retractable sheathpositioned around at least a portion of the elongate delivery catheter,where the retractable sheath moves longitudinally relative the elongatedelivery catheter; a circulatory valve positioned between the elongatedelivery catheter and the retractable sheath, where the circulatoryvalve includes a valve frame having frame members defining frame cellswith joints in opposing relationship, and a valve leaflet coupled to thevalve frame; and deployment threads that extend longitudinally betweenthe elongate delivery catheter and the retractable sheath to the jointsof the frame cells, where force applied through the deployment threadstransitions the joints from a first stable equilibrium state through anunstable equilibrium state to a second stable equilibrium state.
 11. Thesystem of claim 10, where the retractable sheath moves longitudinallyrelative the elongate delivery catheter to allow the circulatory valveto move from an undeployed state to the first stable equilibrium state.12. The system of claim 11, where the first stable equilibrium state iseighty (80) to ninety-five (95) percent of the second stable equilibriumstate.
 13. The system of claim 10, including a push tube that extendslongitudinally between the elongate delivery catheter and theretractable sheath to abut at least one of the joints, and where thedeployment threads extend through the push tube to the joints of theframe cell to allow force to be applied to the joints between thedeployment threads and the push tube.